Functional nanomachines: Recent advances in synthetic molecular machinery

A mini-review: As the top-down approach for miniaturisation of technology reaches its inherent limitations, robust strategies to build nanoscale machinery components, which have the ability to convert an input energy into motion, from the molecular level up, become increasingly important. Nature is certainly the most proficient in the control of molecular level motion; nevertheless, many successes have been enjoyed in the pursuit of mimicking key aspects of nature’s molecular machines, including two state switches, ion pumps, unidirectional rotary motors and molecular robots that can move molecular cargo. This mini-review outlines of some of the most impressive recent examples towards this end.     

Single-molecule DNA logic nanomachines based on origami

<正>Nowadays, it is a truism that chemists, bioengineers and others must be schooled in cell and molecular biology, including knowledge of the cellular, elemental and molecular building blocks of living systems. Inspired by exquisite and efficient biomolecular machines in living cells, such as ATPases that catalyze the decomposition of ATP into ADP and free phosphate ion, researchers representing multiple dis-     

Electron-capture mass spectrometry: recent advances

Electron-capture (EC) is a sensitive and selective ionization technique for mass spectrometry (MS). In the most familiar form of EC, a susceptible analyte (electrophore) is detected after eluting from a gas chromatography (GC) column, where a low attomole detection limit for standards is routine. High-performance liquid chromatography can facilitate sample cleanup prior to detection by GC-EC-MS, but carryover and shifts in retention time for the "invisible" analyte can be difficulties. Solid-phase extraction avoids these difficulties, but the degree of cleanup and recovery can be problems. Alternative electrophoric derivatizing reagents are available to help deal with interferences, and new reagents such as "AMACE1" are emerging. Releasable forms of electrophores can be used as tags for labeling macromolecules, motivated by the desire to multiplex ligand-type assays. The conventional, gas-phase ion source for EC is not well-understood, especially the role of wall reactions. Using an electron monochromator to tune the electron energy adds to the selectivity and information provided by EC-MS. High-resolution and tandem EC-MS measurements are emerging. Electron-capture dissociation is a new technique to sequence small- to medium-sized peptides, having the advantage of providing more extensive sequence information relative to other MS techniques. Particle-beam EC-MS tends to be less sensitive than GC-EC-MS, but not always. Recently it was demonstrated that EC-MS can be accomplished on an ordinary laser desorption time-of-flight mass spectrometer, and also by using atmospheric pressure chemical ionization. Two applications are discussed here in detail: bile acids and oxidized phenylalanine. EC-MS is well-established as a useful technique for trace analysis in special cases, and the scope of its usefulness is broadening (qualitative analysis and detection of more polar and larger molecules), based on advances in both the chemical and instrumental aspects of this technique.     

Boronic acid based dynamic click chemistry: recent advances and emergent applications

Recently, reversible click reactions have found numerous applications in chemical biology, supramolecular chemistry, and biomedical applications. Boronic acid (BA)-mediated cis-diol conjugation is one of the best-studied reactions among them. An excellent understanding of the chemical properties and biocompatibility of BA-based compounds has inspired the exploration of novel chemistries using boron to fuel emergent sciences. This topical review focuses on the recent progress of iminoboronate and salicylhydroxamic–boronate constituted reversible click chemistries in the past decade. We highlight the mechanism of reversible kinetics and its applications in chemical biology, medicinal chemistry, biomedical devices, and material chemistry. This article also emphasizes the fundamental reactivity of these two conjugate chemistries with assorted nucleophiles at variable pHs, which is of utmost importance to any stimuli-responsive biological and material chemistry explorations.

Fundamental progress, current developments, and rapidly growing applications of iminoboronate and salicylhydroxamic–boronate conjugate esters are deliberated.     

Curcumin as a photosensitizer: From molecular structure to recent advances in antimicrobial photodynamic therapy

Nowadays multi-drug resistant microorganisms is a serious public health problem worldwide. To overcome it, new antimicrobial strategies have been developed. Among them, antimicrobial photodynamic therapy is an efficient tool against various micro-organisms in different medical and healthcare fields. The antimicrobial photodynamic protocol is based on the interaction of a photosensitizer, molecular oxygen, and an appropriate light source. Herein, we described the main physical and chemical proprieties of curcumin, an useful natural photosensitizer, including its degradation pathways, analytical methods for quantification, extraction method, synthetic methodologies, and pharmaceutical formulations used. Moreover, a comprehensive review of the past 10 years (2010−2019) concerning the application of curcumin as photosensitizer against microorganisms is described and discussed.     

Triphenylene-based discotic liquid crystals: recent advances

Since the early work of Chandrasekhar and his co-workers on hexaesters of benzene published in 1977, discotic liquid crystals (DLCs), in particular, triphenylene-based DLC materials have been investigated intensively, especially over the last decade. The first successful commercialisation of triphenylene-based DLCs has been accomplished in Fuji ‘Wide-View’ optical compensation films. DLCs represent a broad well understood class of soft matter which possess the ability to self-organise into highly anisotropic and ordered structures such as columns that function not only as organic anisotropic semiconductors, but also contribute to the development of new smart materials in the field of organic electronics for many device applications such as photovoltaic devices, light-emitting diodes, field-effect transistors, memory elements, and sensors. Over the last 35 years, more than 1000 triphenylene derivatives have been synthesised and investigated starting from structure-properties to structure-device performance relationships. The very first review by Cammidge and Bushby followed by Kumar summarised the chemistry and physical properties of triphenylene-based discotics up to 2003. In this review, progress in the research of triphenylene DLC materials since 2004 is comprehensively outlined.     

An interlocked coordination cage based on aromatic amide ligands

An interlocked M_4 L_8 coordination cage was synthesized by coordination-driven self-assembly of palladium(Ⅱ) ions with aromatic amide bidentate ligands.The reaction of the ligand and the metal at 2:1 ratio led to the monomeric M_2 L_4 cage as the kinetic product,while the thermodynamic product M_4 L_8 cage was obtained by prolongating the reaction.This conve rsion and the interlocked structure was clearly revealed by using ~1 H NMR,mass spectrometry and X-ray crystallography.The driving force of interlocking was mainly attributed to the interactions(hydrogen bonding,aromatic stacking and electrostatic interaction) arising from the aptitude of flexibility of the amide ligand.     

Theranostic radionuclides: recent advances in production methodologies

Journal of Radioanalytical and Nuclear Chemistry - Various concepts involved in the quantification of radiation dose while following the theranostic approach in nuclear medicine are outlined. The...     

The organocatalytic vinylogous aldol reaction: recent advances

Over the past decade, organocatalysis has emerged as a powerful tool for stereoselective carbon-carbon bond formation under exceptionally mild conditions. The organocatalytic versions of a large number of traditional synthetic transformations are now well established and the quest for new applications of the basic concepts of organocatalysis continues. This review addresses the emergent interest in the organocatalytic vinylogous aldol reaction. While noteworthy progress has been made in this area, significant challenges lie ahead.     

Coronarenes: recent advances and perspectives on macrocyclic and supramolecular chemistry

Synthetic macrocyclic host molecules always play an essential role in the establishment and development of supramolecular chemistry. Along with the continuous interests in the study of classical macrocycles, recent decades have witnessed the emergence and rapid development of the chemistry and supramolecular chemistry of novel and functional macrocycles. Owing to their easy availability, a self-tunable V-shaped cavity resulted from 1,3-alternate conformation, and diversified electronic features steered by the interplay between heteroatom linkages and aromatic rings, heteracalixaromatics act as a type of versatile and powerful macrocyclic hosts in molecular recognition and fabrication of supramolecular systems. Very recently, by means of engineering the bond connectivity or the recombination of chemical bonds within heteracalixaromatics, we have devised coronarenes, a new generation of macrocycles. In this concise review, macrocyclic and supramolecular chemistry of coronarenes are summarized in the order of their syntheses, structural features, molecular recognition and self-assembly properties. In the last part of this article, personal perspectives on the study of macrocyclic and supramolecular chemistry will also be discussed.     

Chiral thioether-based catalysts in asymmetric synthesis: recent advances

Chiral, non-racemic, thioethers have provided organic chemists with useful tools for developing new reagents and catalysts for practical modern asymmetric synthesis. Disclosed herein is a brief personal overview on major recent contributions in this field in which the sulfur atom plays a leading role in the reaction pathway.     

Review on recent advances of carbon based adsorbent for methylene blue removal from waste water

The growth in textile and printing industries proven detrimental to the aquatic environment as the industrial waste containing dye seeped into the ecosystem. A high concentration of dye in water possess negative impacts on water ecosystem and harmful to human health. Removal of methylene blue (MB) dye from industrial waste via adsorption pathway has been widely investigated that promised high efficiency of MB removal. This review will summarize researches published from 2008 to 2019 on the removal of MB using carbon adsorbent with focus will be given on the synthesis and modification of carbon-based materials, and the structural properties influencing the performance of MB adsorption. Summary on the type of material used for the synthesis of carbon materials (activated carbon and biochar) will be included from utilization of the naturally occurring carbon sources such as polymers, biomasses and biowastes, and also sucrose and hydrocarbon gases. Modification of carbon materials such as chemical activation and physical activation; surface grafting to form functionalized surfaces; deposition with metal and magnetic nanoparticles via impregnation; and manufacturing of carbon composites will be discussed on the effects to promote MB adsorption and desorption. Another type of carbon adsorbents such as porous carbon; graphitic carbons including graphite, graphene, graphene oxide, and carbon nitride (g-C₃N₄); and finally nanocarbon in the form of nanotube, nanorod and nanofiber; will be included in the review with details on the synthesis method and the correlation between structural properties and adsorption activity. The regeneration process to increase the life cycle of carbon adsorbent will also be discussed based on two regeneration pathway i.e. a thermal degradation and desorption on MB. Finally the thermodynamics, kinetics, and the adsorption models of MB on carbon adsorbent will be discussed in this review.     

Catalysis in glycerol: a survey of recent advances

There is currently a significant increase in the use of glycerol as a renewable solvent for catalytic reactions. Glycerol has often been the solvent of choice in both homogeneous and heterogeneous catalyses, despite its high viscosity at ambient temperature and the low solubility of highly hydrophobic reagents found in glycerol. Its biodegradability and non-toxicity have led to reports of improved reaction performance and selectivity, as well as easier product separation and effective catalyst recycling. All relevant advances in this emerging field of “green” catalysis are thoroughly reviewed below.     

Recent advances in enhancing reactive oxygen species based chemodynamic therapy

Chemodynamic therapy(CDT), defined as an in situ oxidative stress response catalyzed by the Fenton or Fenton-like reactions to generate cytotoxic hydroxyl radicals(·OH) at tumor sites, exhibits conspicuous inhibition of tumor growth. It has attracted extensive attention for its outstanding edge in effectiveness,lower systemic toxicity and side effects, sustainability, low cost and convenience. However, the inconformity of harsh Fenton reaction conditions and tumor microenvironment hamper its fur...     

Ferroelectric liquid crystalline elastomers: from the analysis of the molecular dynamics to the design of nanomachines

In ferroelectric liquid crystalline elastomers (FLCE) the properties of ferroelectric liquid crystals are combined with that of polymeric networks. With use of refined synthetic techniques, it is possible to align the chiral mesogenic groups in FLCE on a macroscopic scale (∼cm²). By employing that set of methods, the development of a new class of materials has been achieved having an extraordinary profile of features, among them the following: (1) FLCE are piezoelectric because of the ferroelectric order of the chiral mesogens and because of the fact that the polymeric network prevents flow. (2) Due to a photochemically or thermally induced cross‐linking reaction the viscoelastic properties of FLCE can be adjusted over a wide range. (3) The coupling between the elastomeric network and the (polar) chiral mesogens can be modified by chemical engineering, hence offering the possibility to tailor the piezoelectric as well as the viscoelastic properties of FLCE. (4) It is possible to prepare thick (∼ 100 μm), thin (∼ μm), and ultrathin (∼ nm) films of macroscopically oriented FLCE, as self‐supporting or as transferred samples. With this combination of properties FLCE have made a strong technological impact as basic materials for sensors and soft actuators in the area of microsystems technology. The present contribution is focused on the piezoelectric effect in FLCE and its molecular interpretation.     

Measurement of endogenous estrogens: analytical challenges and recent advances

Recent developments in the analysis of endogenous estrogens (including both free and conjugated estrogens) are reviewed. Largely due to urging by some cancer researchers, new demands are now being placed on such measurements in terms of sensitivity, throughput, multi-analyte detection and accuracy. Especially high sensitivity is required for detecting estrogens in serum from postmenopausal women, children and men, where concentrations at the low pg/ml level are encountered, and one would prefer to test much less than 1 ml of serum. Aside from throughput, meeting all of these demands may be beyond the reach of immunoassay, the method that has created and continues to dominate this field. Both HPLC and GC versions of mass spectrometry are emerging that have some potential to improve the testing of physiological samples for endogenous estrogens. The following topics are covered in this review: related analyses (e.g. detection of estrogens in environmental samples such as water, where 1-l samples can be collected to provide ng amounts of estrogens); structure and metabolism of estrogens; biological actions (with an emphasis on their role in cancer); immunoassays; HPLC with electrochemical detection; GC-ECD; and various forms of mass spectrometry.     

Gold nanoparticles in biomedical applications: recent advances and perspectives

Gold nanoparticles (GNPs) with controlled geometrical, optical, and surface chemical properties are the subject of intensive studies and applications in biology and medicine. To date, the ever increasing diversity of published examples has included genomics and biosensorics, immunoassays and clinical chemistry, photothermolysis of cancer cells and tumors, targeted delivery of drugs and antigens, and optical bioimaging of cells and tissues with state-of-the-art nanophotonic detection systems. This critical review is focused on the application of GNP conjugates to biomedical diagnostics and analytics, photothermal and photodynamic therapies, and delivery of target molecules. Distinct from other published reviews, we present a summary of the immunological properties of GNPs. For each of the above topics, the basic principles, recent advances, and current challenges are discussed (508 references).     

Metal-free organic dyes for dye-sensitized solar cells: recent advances

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